Determination of pump type

The type of pump is mainly determined by the amount of air required for operation, vacuum or exhaust pressure.

When the pump is working, you need to pay attention to the following two aspects:

1. As far as possible, it is required to operate in the high-efficiency area, that is, in the area of critical vacuum or critical exhaust pressure.

2. Avoid running near the maximum vacuum or maximum exhaust pressure. Running in this area is not only extremely inefficient, but also unstable, prone to vibration and noise. For vacuum pumps with high vacuum, cavitation often occurs when operating in this area. The obvious sign of this phenomenon is noise and vibration in the pump. Cavitation can cause damage to the pump body, impeller and other parts, so that the pump cannot work.

According to the above principles, when the vacuum degree or gas pressure required by the pump is not high, it can be preferentially selected among the single-stage pumps. If the vacuum degree or exhaust pressure is high, the single-stage pump is often not satisfied, or the pump is required to have a large gas volume under the condition of a higher vacuum degree, that is, the performance curve is required to be flat at a higher vacuum degree, and a two-stage pump can be selected. If the vacuum degree is required to be above -710mmHg, a water ring-atmosphere pump or a water ring-Roots vacuum unit can be used as the vacuum pumping device.

If it is only used as a vacuum pump, it is better to choose a single-acting pump. Because the single-acting pump has a simple structure, is easy to manufacture and maintain, and has good cavitation resistance under high vacuum conditions.

If it is only used as a compressor with a large air volume, it is more suitable to choose a double-acting pump. Because the double-acting pump has a large air volume, small volume, light weight, and the radial force can be automatically balanced, the shaft is not prone to fatigue fracture, and the pump has a long service life.

Select the vacuum pump according to the air volume required by the system

After initially selecting the type of pump, for the vacuum pump, the model of the pump should be selected according to the air volume required by the system.